-
Archives of Pathology & Laboratory... Feb 2017The direct antiglobulin test (DAT; sometimes referred to as the "Coombs" test) continues to be one of the most widely used assays in laboratory medicine. First described... (Review)
Review
The direct antiglobulin test (DAT; sometimes referred to as the "Coombs" test) continues to be one of the most widely used assays in laboratory medicine. First described about 70 years ago, it is elegantly simple in design, yet it is widely complex in its applications and interpretations, and it is prone to false-positive and false-negative results. The overall objective of our review is to provide practicing pathologists with a guide to identify situations when the DAT is useful and to highlight disease-specific shortcomings as well as general pitfalls of the test. To accomplish these goals, this review will discuss the following: (1) the history of the DAT, (2) how the test is performed in the clinical laboratory, (3) clinical situations for its use, (4) its interpretation, and (5) the pitfalls associated with DAT assays, including causes of false positivity.
Topics: Coombs Test; Humans
PubMed: 28134589
DOI: 10.5858/arpa.2015-0444-RS -
BMJ (Clinical Research Ed.) Jun 2019
Topics: Agglutination Tests; Anti-Bacterial Agents; Chancre; Disease Transmission, Infectious; Female; Humans; Incidence; Luminescent Measurements; Male; Sexually Transmitted Diseases, Bacterial; Syphilis; Syphilis Serodiagnosis; Treponema pallidum
PubMed: 31253629
DOI: 10.1136/bmj.l4159 -
Frontiers in Cellular and Infection... 2021With the Visceral Leishmaniasis/Kala-azar Elimination Program in South Asia in its consolidation phase, the focus is mainly on case detection, vector control, and... (Review)
Review
With the Visceral Leishmaniasis/Kala-azar Elimination Program in South Asia in its consolidation phase, the focus is mainly on case detection, vector control, and identifying potential sources of infection. Accordingly, emphasis is presently on curbing transmission, which is potentially achievable by identification and elimination of potential reservoirs. The strongest contenders for being the disease reservoir are cases of Post Kala-azar Dermal Leishmaniasis (PKDL) which occurs in a minor proportion of individuals apparently cured of Visceral Leishmaniasis (VL). The demonstration of parasites in tissue aspirates despite being a risky and invasive process is the gold standard for diagnosis of VL, but is now being replaced by serological tests e.g., rK39 strip test and direct agglutination test. However, these antibody based tests are limited in their ability to diagnose relapses, detect cases of PKDL, and monitor effectiveness of treatment. Accordingly, detection of antigen or nucleic acids by polymerase chain reaction has been successfully applied for monitoring of parasite kinetics. This review article provides updated information on recent developments regarding the available antibody or antigen/nucleic acid based biomarkers for longitudinal monitoring of patients with VL or PKDL and emphasizes the need for availability of studies pertaining to quantification of treatment response or relapse.
Topics: Animals; Asia; Humans; Leishmania; Leishmania donovani; Leishmaniasis, Cutaneous; Leishmaniasis, Visceral; Parasites
PubMed: 33692966
DOI: 10.3389/fcimb.2021.623437 -
Northern Clinics of Istanbul 2019Brucellosis is a common zoonotic disease with high morbidity. In the majority of human cases, the causative agent is B. melitensis. Infection is transmitted to humans by... (Review)
Review
Brucellosis is a common zoonotic disease with high morbidity. In the majority of human cases, the causative agent is B. melitensis. Infection is transmitted to humans by direct/indirect contact with the contaminated animal products (e.g., consumption of unpasteurized milk), infectious aerosols and aborted fetus. Brucellosis often affects middle-aged adults and young people. Patients with brucellosis tend to have non-specific symptoms, including fever, chills, night sweats, joint pain and myalgia. Brucellosis affects various organs and tissues. The osteoarticular system is one of the most commonly described affected systems in humans. In several clinical studies, the prevalence of Osteoarticular Brucellosis (OB) is reported as 2-77%. Most important osteoarticular clinical forms osteomyelitis, spondylitis, sacroiliitis, arthritis and bursitis. Spondylitis and spondylodiscitis are the most frequent complications. Spondylodiscitis often affects the lumbar (especially at the L4- L5 levels) and low thoracic vertebrae than the cervical spine. Back pain and sciatica radiculopathy are the most common complaints about patients. Sacroiliitis is associated with severe pain, especially back pain in affected individuals. Spinal destructive brucellar lesions are also reported in adults in previous studies. Brucellosis is diagnosed with clinical inflammatory signs (eg. tenderness, pain) of the affected joints together with positive serological tests and positive blood/synovial fluids cultures. Serological test measures the total amount of IgM/IgG antibodies. Standard agglutination test (SAT) titer ≥1:160 is in favor of brucellosis diagnosis. Enzyme-Linked Immunosorbent Assay (ELISA) and Polymerase chain reaction (PCR) are other types of diagnostic tests. Radiological assessments, such as joint sonography, computed tomography, magnetic resonance imaging, are the most helpful radiological methods to diagnose spinal brucellosis. The agents commonly used in the treatment of brucella spondylitis are doxycycline, streptomycin, gentamicin, ciprofloxacin, trimethoprim/sulfamethoxazole and rifampicin. The recommended regimens for treatment of brucella involve two or three antibiotics combinations. No standard treatment, physicians prescribe drugs based on conditions of the disease. Patients need a long-term (usually at three months) antibiotic therapy for mainly aiming to prevent relapses. Surgery may be required for patients with spinal abscess. This review focused on physicians' awareness for osteoarticular involvement, clinical presentation, diagnosis and current treatment of OB.
PubMed: 31909392
DOI: 10.14744/nci.2019.05658 -
Tuberkuloz Ve Toraks Mar 2020Brucellosis is widely distributed zoonotic infection. Brucellosis is a multisystemic disease but pulmonary infection due to brucellosis is very rarely reported. (Review)
Review
INTRODUCTION
Brucellosis is widely distributed zoonotic infection. Brucellosis is a multisystemic disease but pulmonary infection due to brucellosis is very rarely reported.
MATERIALS AND METHODS
We retrospectively evaluated our pediatric brucellosis cases between February 2014 and December 2015. The brucellosis patients with and without pulmonary infection were compared with each other.
RESULT
We detected pulmonary infection in 18 of the 98 brucellosis patients. There was no statistical significant difference between the brucellosis patients with and without a pulmonary infection as regards age, gender, and animal husbandry history. The laboratory findings including the Brucella Coombs agglutination titers were also similar. The most common chest X-ray findings were interstitial infiltration and hilar lymphadenopathy. All of our cases with pulmonary infection recovered with the usual anti-brucella treatment.
CONCLUSIONS
Brucellosis may cause a pulmonary infection more often than thought. The prognosis of respiratory brucellosis is good and the classic treatment regimen is appropriate.
Topics: Animals; Brucella; Brucellosis; Child; Coombs Test; Female; Humans; Lung Diseases, Interstitial; Male; Respiratory Tract Infections; Retrospective Studies
PubMed: 32718139
DOI: 10.5578/tt.69015 -
Frontiers in Cellular and Infection... 2020Toxoplasmosis is a widely distributed zoonotic infection caused by the obligate intracellular apicomplexan parasite . It is mainly transmitted through the ingestion of... (Review)
Review
Toxoplasmosis is a widely distributed zoonotic infection caused by the obligate intracellular apicomplexan parasite . It is mainly transmitted through the ingestion of oocysts shed by an infected cat acting as its definitive host. The key to effective control and treatment of toxoplasmosis is prompt and accurate detection of infection. Several laboratory diagnostic methods have been established, including the most commonly used serological assays such as the dye test (DT), direct or modified agglutination test (DAT/MAT), indirect hemagglutination test (IHA), latex agglutination test (LAT), indirect immunofluorescent test (IFAT), enzyme-linked immunosorbent assays (ELISA), immunochromatographic tests (ICT), and the western blot. Nonetheless, creating specific and reliable approaches for serodiagnosis of infection, and differentiating between acute and chronic phases of infection remains a challenge. This review provides information on the current trends in the serodiagnosis of human toxoplasmosis. It highlights the advantages of the use of recombinant proteins for serological testing and provides insight into the possible future direction of these methods.
Topics: Agglutination Tests; Animals; Antibodies, Protozoan; Cats; Enzyme-Linked Immunosorbent Assay; Humans; Serologic Tests; Toxoplasma; Toxoplasmosis, Animal
PubMed: 32457848
DOI: 10.3389/fcimb.2020.00204 -
BMC Infectious Diseases Nov 2023Parasitological investigation of bone marrow, splenic or lymph node aspirations is the gold standard for the diagnosis of visceral leishmaniasis (VL). However, this... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Parasitological investigation of bone marrow, splenic or lymph node aspirations is the gold standard for the diagnosis of visceral leishmaniasis (VL). However, this invasive test requires skilled clinical and laboratory staff and adequate facilities, and sensitivity varies depending on the tissue used. The direct agglutination test (DAT) is a serological test that does not need specialised staff, with just minimal training required. While previous meta-analysis has shown DAT to have high sensitivity and specificity when using parasitology as the reference test for diagnosis, meta-analysis of DAT compared to other diagnostic techniques, such as PCR and ELISA, that are increasingly used in clinical and research settings, has not been done.
METHODS
We conducted a systematic review to determine the diagnostic performance of DAT compared to all available tests for the laboratory diagnosis of human VL. We searched electronic databases including Medline, Embase, Global Health, Scopus, WoS Science Citation Index, Wiley Cochrane Central Register of Controlled Trials, Africa-Wide Information, LILACS and WHO Global Index. Three independent reviewers screened reports and extracted data from eligible studies. A meta-analysis estimated the diagnostic sensitivity and specificity of DAT.
RESULTS
Of 987 titles screened, 358 were selected for full data extraction and 78 were included in the analysis, reporting on 32,822 participants from 19 countries. Studies included were conducted between 1987-2020. Meta-analysis of studies using serum and DAT compared to any other test showed pooled sensitivity of 95% (95%CrI 90-98%) and pooled specificity of 95% (95%CrI 88-98%). Results were similar for freeze-dried DAT and liquid DAT when analysed separately. Sensitivity was lower for HIV-positive patients (90%, CrI 59-98%) and specificity was lower for symptomatic patients (70%, CrI 43-89%). When comparing different geographical regions, the lowest median sensitivity (89%, CrI 67-97%) was in Western Asia (five studies).
CONCLUSIONS
This systematic review and meta-analysis demonstrates high estimated pooled sensitivity and specificity of DAT for diagnosis of VL, although sensitivity and specificity were lower for different patient groups and geographical locations. This review highlights the lack of standardisation of DAT methods and preparations, and the lack of data from some important geographical locations. Future well-reported studies could provide better evidence to inform test implementation for different patient populations and use cases.
PROSPERO REGISTRATION
CRD42021240830.
Topics: Humans; Leishmaniasis, Visceral; Agglutination Tests; Serologic Tests; Sensitivity and Specificity; HIV Seropositivity
PubMed: 37946107
DOI: 10.1186/s12879-023-08772-1 -
Zoonoses and Public Health Jun 2022Despite public concern on the role of free-roaming cats as reservoirs of zoonotic agents, little is known about the influence of urban and peri-urban landscapes on the...
Despite public concern on the role of free-roaming cats as reservoirs of zoonotic agents, little is known about the influence of urban and peri-urban landscapes on the exposure risk. We evaluated the seroprevalence of three zoonotic agents (Chlamydia felis, Coxiella burnetii and Toxoplasma gondii) in domestic cats (Felis catus). Two hundred and ninety-one free-roaming cats were trapped in Murcia municipality (Southeast Spain), and their sera were tested for specific antibodies against T. gondii using a modified agglutination test (MAT), and for C. felis, C. burnetii and feline immunodeficiency virus (FIV) antibodies with ELISA technique. Pathogen seroprevalence at 95% CI was calculated for each sex and age category (up to and over 12 months) and compared with a chi-squared test. The role of human population density and urban landscape characteristics on the risk of pathogen exposure in the cat population was explored using generalized linear models. Seropositivity against a single pathogen was found in 60% of the cats, while 19% was seropositive for two or three pathogens. Seroprevalence of C. felis was 8% (CI : 5-11), 37% (CI : 31-42) for C. burnetii and 42% (CI : 36-47) for T. gondii. In addition to these three pathogens, FIV seropositivity was low (1%, CI : -0.1 to 2) and adult cats were more likely to be seropositive to C. burnetii than young individuals (OR: 2.3, CI : 1.2-4.2). No sex or age class differences in seroprevalence were observed for the rest of the pathogens. Seropositivity was correlated with water surface areas for C. felis, and not with crop areas. Coxiella burnetii seropositivity was correlated with the percentage of urban areas (continuous with only buildings and discontinuous, that include buildings, parks, and pedestrian and urban green areas), human population size and peri-urban areas with shrubs, and not correlated with other agricultural landscapes (orchards and crop areas). However, the seroprevalence of T. gondii was only associated with agricultural landscapes such as orchards. The detection of hotspot areas of high pathogen exposure risk is the basis for municipal services to implement surveillance and risk factor control campaigns in specific-risk areas, including (a) efficient health management of urban cat colonies by geographical location, population census and health status monitoring of the components of each cat colony, (b) improvement of hygiene and sanitary conditions at the feeding points of the cat colony and (c) free-roaming cat trapping for health monitoring and, in the long term, to know the evolution of the health status of their populations.
Topics: Agglutination Tests; Animals; Antibodies, Protozoan; Cat Diseases; Cats; Chlamydia; Risk Factors; Seroepidemiologic Studies; Toxoplasma; Toxoplasmosis, Animal
PubMed: 35129882
DOI: 10.1111/zph.12919 -
Open Veterinary Journal Sep 2023Neurotropic viruses in the family Rhabdoviridae, genus , are what cause rabies, an acute, progressive, and highly lethal encephalomyelitis.
BACKGROUND
Neurotropic viruses in the family Rhabdoviridae, genus , are what cause rabies, an acute, progressive, and highly lethal encephalomyelitis.
AIM
Evaluation of the used diagnostic techniques to determine the most simple; rapid and accurate test for rabies virus (RABV) recognition in different specimens aiming to reach a rapid diagnosis as a step aid in the disease control and to prevent or even minimize the suspected hazard.
METHOD
The used techniques included an infection trial of Swiss mice with the mice-adapted challenge rabies virus followed by the detection of the virus in the infected mices' brains. Virus detection was carried out through the application BHK21 cell line infection; fluorescent antibody technique; latex agglutination test (LAT); direct enzyme-linked immunosorbent assay (ELISA); rabies antigen detection kit ELISA; conventional polymerase chain reaction (PCR).
RESULTS
It was found that virus inoculation in mice and BHK21 cell lines needs 5-7 days with positivity of 90% and 100%, respectively. Rapid antigen kit was able to detect rabies antigen in mice brains suspension and BHK21 infected fluid within 3-5 minutes with percentages of 60% and 55.5%, respectively. In 1-1.5 hours, the direct fluorescent antibody method (DFAT) detected 90% and 100% of the rabies antigen in BHK21 cell line infection and brain impressions, respectively. Latex agglutination showed clear results with 88.8% with BHK21 infected fluid within 3-5 minutes while it did not carry out on brain emulsions to prevent falsely positive results brought on by the presence of tissue fragments. Conventional one-step PCR revealed 100% positivity with either brain or cell culture preparations within 2 days. Direct ELISA showed 88.8% positivity with BHK21 infected fluid with 1 day of work.
CONCLUSION
Mice inoculation test, cell culture infection; DFAT and PCR are the most accurate techniques for the detection of RABV with a positivity of 90%-100% followed by LAT and ELISA with a positivity of 88.8%, and lastly, rabies antigen ELISA kit (RAK) with a positivity of 55.5%-60% taking in consideration the required time for each. In addition, the positivity % of the applied tests revealed their sensitivity and specificity.
Topics: Animals; Mice; Rabies virus; Rabies; Lyssavirus; Sensitivity and Specificity; Cell Culture Techniques
PubMed: 37842113
DOI: 10.5455/OVJ.2023.v13.i9.13